Single-serving coffee makers have become more popular in recent years. Most single-serving machines use a pressure pump to deliver heated liquid or water during the brewing process. Many different pressure- or fluid-tight locking mechanisms have therefore been developed for pressurized coffee makers. These locking mechanisms typically use a slider to lock or secure the brew head of the coffee maker. For instance, WO2004028318 (see also U.S. Pat. No. 6,995,015) describes a locking mechanism that uses a toggle joint lever system to move the slider to the open or closed position. One disadvantage of using a toggle joint lever system to move the slider is that, for proper operation, the lever can only be mounted on the front center of the brew head.
The gear-driven rocking assembly of the present invention allows the lever to be placed or located either on the top, rear, side or in the front of the brew head assembly. The construction of the present invention is more dynamic and flexible, and can be adapted for sliding or rotating the locking member or element between a locked and an unlocked position. An advantage of the gear-driven locking assembly of the present invention is that only a small force is required to turn the lever for locking. In one embodiment, the locking assembly is capable of withstanding pressures up to 4 bars. In another embodiment, the locking assembly is capable providing fluid- and/or pressure-tight seal up to 20 bars. Typically for a single-serve brewing device, a locking assembly capable of maintaining fluid- and/or pressure-tight seal up to between 3-4 bars may be sufficient. For an espresso machine, however, a locking assembly capable of providing fluid- and/or pressure-tight seal at higher pressures, preferably between 15-20 bars, may be required. In a locking assembly of the present invention adapted for maintaining fluid- and/or a pressure-tight seal up to 20 bars, the components, such as the seal, locking cam(s) and corresponding recess(es), are provided with increased strength.